Extracts produced by different strains of roaches, including the USDA Reference German Cockroach strain have been subjected to IEF and immunoblotting. Extracts have been prepared from the Alaskan Brown Cockroach and the Brown Banded Cockroach, in addition to extracts prepared from only males or only female source materials of both American and German cockroaches. Qualitatively, allergenic composition appears to differ within each strain; attempts to quantitate these differences will begin with the acquisition of an allergic serum pool.